Yesterday's preference for AT&T Inc. calls over puts was unusual

In yesterday's trading, AT&T Inc. (NYSE:T) call volume doubled put volume. Most active was the May 37 call, where close to 6,300 contracts were exchanged. For comparison, volume on the next most active strike was fewer than 3,100 contracts.

The majority of the contracts at the May 37 call crossed at the ask price, suggesting the options were bought. Also, open interest soared overnight at the strike, hinting at newly bought bullish bets. In short, the out-of-the-money call buyers are aiming for T -- presently hovering at $35.53 -- to surmount the strike by the close on Friday, May 16, when back-month options expire.

Given the fact that nearly 4% of AT&T's float is sold short -- which would take more than eight sessions to cover, at the stock's average daily trading pace -- it's also possible the calls were purchased by short sellers to lock in a maximum exit price in the event of a rally. Whatever the motive, the most the buyers will forfeit is the initial premium paid, should T be perched below $37 at May options expiration.

Taking a step back, yesterday's penchant for long calls was a bit unusual, relative to recent history. The stock has racked up a 10-day International Securities Exchange (ISE), Chicago Board Options Exchange (CBOE), and NASDAQ OMX PHLX (PHLX) put/call volume ratio of 1.55. In other words, during the last two weeks, 1.55 puts have been bought for every call. This ratio ranks in the 94th percentile of its annual range, suggesting traders have rarely scooped up puts (relative to calls) with greater rapidity.

Technically speaking, such pessimism appears to be warranted. AT&T Inc. (NYSE:T) is up less than 2% year-to-date, and is sitting in negative territory on a year-over-year basis. What's more, the telecom firm is slated to step into the earnings confessional after the close on Tuesday, April 22. The last time around, despite besting analysts' consensus earnings-per-share estimate, T shed 3.7% in the subsequent week.